This walkthrough needs JavaScript. In short: a service mesh, as this practice designs it, puts a proxy beside each of two thousand services. The control plane compiles configuration ahead of time and is never asked anything while a request is being forwarded, so every proxy forwards on three things it already holds: its last configuration, a trust bundle and an unexpired identity. Told as a model railway: the planning office prints a bulletin, the gatehouse keeps the last one on the wall, and the trains never wait for the office.